In a wireless communication system such as a mobile cellular communication system, a wireless local area network, or fixed wireless access, abase station or a communication node such as an access point, a relay station, and a user equipment generally has a capability of transmitting its own signal and receiving a signal of another communication node. In a wireless full duplex technology, receiving and transmitting operations are simultaneously performed on a same wireless channel, and theoretically, spectral efficiency is twice that of a conventional frequency division duplex or time division duplex technology, so the wireless full duplex technology gradually becomes a next generation communication hotspot technology to which attention is paid. The premise of implementing wireless full duplex lies in avoiding, reducing, and eliminating strong interference of a transmit signal of a same transceiver to a received signal as much as possible, so that the transmit signal does not affect correct reception of a wanted signal.
Moreover, in a wireless communication system, the propagation environment is far more complex than that of point-to-point wireless communication, a radio signal is mainly propagated in a non-line-of-sight manner, the distance between two communication ends may be as far as several hundreds of meters or larger, and MIMO is widely applied to these systems. For example, in a mobile cellular communication system such as LTE or UMTS, a base station is configured with at least two transmit antennas and two receive antennas, and a power difference between a received signal and a transmit signal may generally be up to 80 dB to 140 dB or even larger. In these systems, in the conventional wireless full duplex technology, a radio signal of each transmit antenna may be coupled to each receive antenna in a MIMO scenario, while in the prior art, self-interference of a single transmit antenna or a part of transmit antennas can only be canceled, and interference suppression efficiency is not high, so the interference signal in a full duplex multi-antenna system cannot be effectively eliminated.